EP0458011B1 - Pipe component, especially for the exhaust conduit of internal combustion engines - Google Patents

Description

The invention relates to a line element, in particular for the exhaust gas line of internal combustion engines, consisting of a corrugated and / or a metal hose wound from at least one band with means arranged outside the metal hose along this and connected to the connection ends of the metal hose for flexible support of the metal hose against operational changes in length .

Such flexible line elements used in the exhaust pipe of motor vehicles are generally known and widely used. They are used to compensate for operational relative movements between the engine on the one hand and the exhaust pipe, which is usually permanently installed on the vehicle floor, possibly with the aid of flexible support parts, and also to decouple or dampen the engine vibrations with respect to the vehicle body.

The metal hose of such line elements can consist of a single-wall or multi-wall corrugated hose or also of a winding hose which is profiled in such a way that a tightness that meets the requirements is achieved. This can e.g. B. can be an agraff hose through the helical Winding at least one metal strip is produced by folding adjacent strip edges together. Combinations of these two types of hose are also possible, as is known, for example, from EP-AO 282 689, according to which an agraff hose is arranged within a corrugated hose. So that the flexible metal hose cannot unduly lengthen, it is provided with a longitudinal support which keeps the two ends of the metal hose at a certain maximum distance. To form this longitudinal support, it is common to place a hose made of metal wire mesh around the metal hose, which hose is firmly connected to the ends of the metal hose, for example by clamping it between the metal hose ends and clamping rings placed on them, and clamping or welding them to these parts . Since such a braided hose has the property of reducing its diameter when it is stretched, when the metal hose is elongated, this leads to the braided hose laying against the outside of the metal hose and thus preventing a further increase in the distance between the two metal hose ends .

Other longitudinal supports can be provided by ropes or wires attached to the ends of the metal hose. A hose wound from a metal band, such as an agraff hose, is also suitable for longitudinal support, since its length increase has a certain design-related limit.

The known line elements outlined above work satisfactorily and have proven themselves. However, there are increasing operating conditions that the Line elements and in particular the impact on the longitudinal support. Just think of the fashionable off-road vehicles. These shock loads affect not only the question of the change in length of the metal hose but also its load due to lateral or angular misalignment between its two ends. If such loads occur suddenly, this leads to local tension increases, which can damage both the longitudinal support and the metal hose prematurely and thus make them unusable.

The object of the invention is therefore to develop a line element of the type mentioned in such a way that there is a reduction in stress peaks from the tensile or compressive stress, from the lateral and angular movement and from external influences, by such stresses in their effect be dampened or cushioned.

Starting from a line element of the type mentioned at the outset, this object is basically achieved in that an annular, flexible, resilient damping cushion made of heat-resistant material is arranged between the metal hose and the means for longitudinal support, and that the longitudinal support is expanded radially in a barrel shape between its ends.

By means of this measure according to the invention, a lossy "spring element" in the form of the damping cushion is thus introduced between the metal hose and the longitudinal support, which supports the radial relative movement between the metal hose and longitudinal support buffers, so that this movement can no longer take place suddenly with a correspondingly heavy load. Here, as will be shown later, it is above all also readily possible to give the spring characteristic or damping characteristic of the damping cushion a different shape, in particular a progressive shape as the load increases.

For the formation of the longitudinal support, it is also expedient in this case to design it as a hollow cylindrical metal wire mesh. There is also the possibility, however, that the longitudinal support is formed by a tubular, radially widened part between the ends, which has axially parallel slots arranged between its ends evenly distributed over the circumference.

Another possibility is that the longitudinal support is formed by wires, ropes or the like which are evenly distributed over the circumference of the metal hose and are axially parallel to the metal hose and which are fixed at their ends to the ends of the metal hose or at least indirectly attached.

In a further embodiment of such an object, it may be expedient that a hollow cylindrical support jacket is provided radially outside the longitudinal support and that the support jacket is axially fixed, for example with one of its ends is fixed to the associated end of the metal hose. This design also results in the desired suspension or damping property with regard to compression, ie Shortening of the length of the metal hose, in that the longitudinal support and damping cushion want to expand radially in the case of such a compression, but cannot because the system comes into contact with the support jacket.

In the simple case, a piece of pipe can be used to form this support jacket. However, it may be expedient for the support jacket to be a flexible metal hose, in particular an agraff hose. Such a component is inexpensive to manufacture and, on the other hand, sufficiently flexible so as not to impede the line element with regard to its operational movements.

As far as the design of the cushioning cushion is concerned, there are extremely numerous possibilities for this, so that it can only be attempted below to emphasize particularly expedient and advantageous configurations without unduly restricting the principle according to the invention. Particular attention is paid to resistance to high temperatures, such as occur in exhaust pipes, while at the same time being simple and inexpensive to manufacture. A damping cushion made of rubber-elastic material, which should not be excluded, would be comparatively problematic with regard to the choice of material in view of the high temperatures that occur.

It has therefore proven to be expedient for the damping cushion to consist of a knitted metal wire and / or knitted metal fiber and / or woven metal wire and / or woven metal wire. These materials can be easy and cheap to produce in large quantities and then press together to the desired shape of the cushion, the degree of compression is basically the possibility to adjust the spring or damping characteristics of the cushion more or less hard or soft. This can be supplemented or supported by introducing appropriate fillers and / or lubricants.

Based on this basic design idea, it can be provided that the damping cushion extends over substantially the entire length of the metal hose between its connection ends. This results in an essentially hollow cylindrical structure with a barrel-shaped outer contour.

On the other hand, there is in principle the possibility that at least one damping cushion extends over an axial partial area of the metal hose. Here, for example, an annular damping cushion can be provided on the longitudinal center of the metal hose. However, there is also the possibility that the damping cushion consists of several rings that are distributed over the length of the metal hose and are shaped accordingly, which can be adjacent to one another, but can also be arranged at an axial distance from one another, depending on which properties of use are sought in the individual case.

As already mentioned, it is expedient that the damping cushion is preformed in accordance with its final installation situation. To further support this design, it is advantageous that the damping cushion has a covering, which can be a braid covering, a covering made of steel wool, a metal foil, a knitted covering or the like. Such a covering is particularly expedient if the cushioning cushion or its individual parts do not have any support with respect to a neighboring part. Such a situation exists, for example, if several axially spaced rings form the damping cushion or if the longitudinal support of the metal hose consists of ropes or wires, between which there are larger gaps distributed parallel to the metal hose over its circumference.

There are also various possibilities for setting the suspension or damping characteristics of the damping cushion. The different degrees of compaction of the material forming the damping cushion have already been mentioned. Further possibilities are that the damping cushion is constructed in several layers, that is to say in a sandwich-like manner, in which case each of these layers can be given its own characteristic through different design and compression, which then leads to a certain behavior for all layers. It is particularly possible here to achieve a progressive suspension or damping characteristic by axially or radially connecting soft and hard layers, by means of which the suspension or damping behavior is relatively soft for smaller loads, but on the other hand hardens with increasing load.

In addition to the different degree of compression of the layers of the cushion, there is also the possibility of producing the layers of the cushion from different materials, for example, on the one hand from a pressed metal wire-knitted and on the other hand from a metal fiber knit to take advantage of the particular properties of these materials.

Another possibility can also consist, for example, of designing the damping cushion as an annular hollow body.

In order to fix the damping cushion in the axial direction with respect to the metal hose, if the metal hose is designed as a corrugated hose, it may be expedient that the inner circumference of the damping cushion is molded into at least one revolution of the hose corrugation. This form fit can of course also be applied to the prefabrication of the cushion.

Fig. 1

einen Axialschnitt durch ein Leitungselement der erfindungsgemäßen Art mit einer ersten Ausbildung des Dämpfungskissens;

Fig. 2

eine Teilansicht des Gegenstandes gemäß Fig. 1 mit einer anderen Ausbildung des Dämpfungskissens;

Fig. 3

eine weitere Ausführung nach der Erfindung, teilweise axial geschnitten;

Fig. 4 bis 7

Varianten in der Ausbildung des Dämpfungskissens;

Fig. 8

eine besondere Ausbildung der Längsabstützung;

Fig. 9

eine weitere Variante hinsichtlich Ausbildung der Längsabstützung und des Dämpfungskissens und

Fig. 10

die Ausbildung eines Leitungselementes mit gleichzeitiger gedämpfter Druckabstützung.

Further features and details of the invention result from the following description of embodiments, which are shown in simplified form on the drawing. The drawing shows:

Fig. 1

an axial section through a line element of the type according to the invention with a first embodiment of the damping cushion;

Fig. 2

a partial view of the object of Figure 1 with a different design of the cushion.

Fig. 3

a further embodiment according to the invention, partially cut axially;

4 to 7

Variants in the design of the cushion;

Fig. 8

a special training of the longitudinal support;

Fig. 9

another variant with regard to the design of the longitudinal support and the cushion and

Fig. 10

the formation of a line element with simultaneous damped pressure support.

The line element shown in FIG. 1 has an inner metal hose 1, which can be a corrugated hose or metal bellows, a winding hose, for example an agraff hose, or a combination of these two hoses. The metal hose 1 is connected at its two ends to connecting pieces 2, 3 for connection to further pipes of the exhaust pipe, not shown.

The metal hose 1 is accompanied on the outside by a longitudinal support 4, for example a braided hose made of metal wire, the ends of which are fixed at the ends of the metal hose 1 by rings 5, 6 which are pressed from the outside against the ends of the metal hose 1 or welded to them.

Between the metal hose 1 and the longitudinal support 4 there is a hollow cylindrical damping cushion 7 which is barrel-shaped in its outer contour and extends over the entire length of the metal hose 1 between its ends. The damping cushion 7 can be made from a knitted metal wire, metal fiber, metal mesh or Metal mesh pressed together and thereby brought to the shape shown in Fig. 1.

If the metal hose 1 wants to lengthen due to operational reasons, this leads to the longitudinal support 4 causing it to want to contact the outside of the metal hose 1, that is to say to stretch it. This movement is hindered or braked by the damping cushion 7, so that, in particular in the case of sudden loads, no hard loading of the metal hose 1 or of the longitudinal support 4 can take place.

This suspension or damping effect occurs equally if a lateral movement, an angular movement or a torsional movement takes place between the ends of the metal hose 1.

FIG. 2 shows a variant of the object according to FIG. 1, in that the damping cushion 8 is designed as a hollow ring, which results in correspondingly modified suspension or damping properties, which are initially very soft, but later are increasingly harder.

FIG. 3 shows a metal hose 10, which is produced by winding a metal strip and is longitudinally supported by a braided hose 11, which is again fixed at the ends by clamping rings 12, 13 to the ends of the metal hose 10.

A damping cushion 14, which may consist of a metal fiber knit, is arranged between braided hose 11 and metal hose 10.

As can be seen, the clamping rings 12, 13 are flared outwards in the direction of the center of the metal hose 10, so that here the braided hose 11 can roll off tension-free during movements between the ends of the metal hose 10.

FIG. 4 shows the object according to FIGS. 1 and 3, the metal hose 15 being designed as a corrugated hose, of which only one shaft 16 is shown.

The longitudinal support is in turn provided by a braid jacket 17 which is fastened to the ends of the metal hose 15 in the manner already described.

A damping cushion 18 is arranged between the metal hose 15 and the braided sheath 17, which is also designed in the manner already described, but with the special feature that a projection 19 encircling the inside of the damping cushion 18 engages in the shaft 16 and thus counteracts the damping cushion 18 in the axial direction Moving secures so that the damping cushion cannot slip axially on the metal hose 15. For assembly, the damping cushion is divided at least once at 18 '' in the radial direction, so that it can be slightly bent up for installation.

FIG. 4 also shows an example of how a component 18 ′ of other suspension and damping properties can be embedded in a damping cushion 18, surrounded on all sides by the damping cushion 18.

Fig. 5 shows more in detail a metal hose 20 in the form of a corrugated hose with longitudinal support 21 through a braid jacket. Here, the damping cushion 22 is provided with two inner projections 23, 24 which, for the reason mentioned above, engage in waves in the metal hose 20 and thus fix the damping cushion 22 in the axial direction on the metal hose 20. Here, too, it is expedient to form the damping cushion at least once.

Fig. 6 shows a variant of the object according to Fig. 5. Here is a metal cushion 25 with longitudinal support 26, a cushion 27 in the form of a short in the axial direction, again expediently divided ring placed with an inner projection 28 in one of the waves of Corrugated hose 25 engages and is thereby fixed in the axial direction on the corrugated hose 25.

6 thus shows, using the example, that the damping cushion 27 does not necessarily have to cover the entire axial length of the inner metal hose 25 if the respective operating conditions permit a smaller volume of the damping cushion.

Fig. 7 shows in a further development of the object according to Fig. 6 in conjunction with Fig. 5 that starting from a metal hose 29 with longitudinal support 30, the damping cushion can also be composed of several rings 31 to 35 lying side by side in the axial direction, which in the case of Fig. 7 lie against each other. Of course, a variant is also possible according to which these rings have an axial distance from each other. This is easy to imagine if you think away rings 32 and 34, for example.

It can be common to all of the previously described embodiments that the damping cushion is encased for shape stabilization, for example by a metal foil or by braiding. This is particularly expedient in the embodiments according to FIGS. 6 and 7, since there the damping cushions 27 or 31 to 35 do not partially abut adjacent components over their entire circumference.

Fig. 8 shows a special design for the longitudinal support of a metal hose 36 in the form of an annular corrugated hose. A damping cushion 38 in the form of a short ring seen in the axial direction is arranged between the longitudinal support 37 and the metal hose 36, as has already been described with reference to FIG. 6. The ring 38 engages with an inner projection 39 in the profiling of the metal hose 36.

The longitudinal support 37 is made from a relatively thin-walled tube in that this tube is radially widened in a barrel shape in its longitudinal center and has been provided with axially parallel slots 40 distributed uniformly over the circumference, through which longitudinal webs 41 of the longitudinal support remain.

The ends of the longitudinal support 37 are fixed in the present case together with the ends of the metal hose 36 on connecting pieces 42, 43 through which the connection with the further pipes of the exhaust system, not shown.

Also in the case of FIG. 8, the outer diameter of the longitudinal support 37 wants to be reduced when the metal hose 36 is elongated, so that the same effects already described with reference to FIG. 1 result, including the behavior when the metal hose 36 is between its ends Is subjected to lateral or angular misalignment or is subjected to torsional loads.

9 shows, based on the object according to FIG. 8, a design in which a metal hose 44 in the form of an annular corrugated hose is present. Here, however, the longitudinal support is formed by wires or ropes 45 which are evenly distributed over the circumference and fixed to the ends of the metal hose 44 and span a damping cushion 46.

In the case of FIG. 9, the damping cushion 46 is formed by axially parallel layers 47, 48, 49, which may consist of different materials and / or differently compressed material sections, so that the damping cushion 46 as a whole has a differentiated suspension or damping property, in particular can be designed in such a way that the suspension or damping property of the damping cushion 46 also increases with increasing load. Again, it can be provided that the individual layers 47 to 49 are stabilized in terms of their shape by a covering. The inner layer 49 could also be provided with at least one inwardly projecting, circumferential projection in order to achieve this Fix damping cushion 46 in the axial direction on the metal hose.

Finally, FIG. 10 shows an example of how, in addition to the previous designs, damping against compression of the metal hose 50, which in turn is a corrugated hose in this case, is also possible. For this purpose, a support jacket 53 is provided outside the longitudinal support 52 enclosing the damping cushion 51, for example in the form of a braided hose, which in the present case has the shape of a hollow cylinder and bears against the longitudinal support 52 on the outside. The support sheath 53 is designed as an agraff tube, which is produced by winding a metal strip in a helical manner and is connected with its one end, in the present case the left end, via an annular web 54 to the associated end of the metal tube 50, while its other end, in the present case right end, is free . A ring 55 placed on the outside serves only for the terminal version of the agraff hose 53.

If the metal hose 50 is now axially compressed or, as seen at least over the circumference by a lateral, angular or torsional movement occurring between its ends, at least partially subjected to a compressive movement, this leads to the longitudinal support 52 being caused radially by the cushion 51 being pushed together wants to expand. However, this movement is blocked by the support jacket 53, so that the damping cushion 51 can also exert its effect against such upsetting movements.

It goes without saying that the addition of a support jacket shown in FIG. 10 is equally suitable for all the previously described embodiments if this appears expedient for operational reasons.

As far as the design of the support jacket 53 is concerned, this can of course also be a rigid tube, for example. However, this would comparatively limit the lateral and angular mobility of the line element, so that the design shown as an agraff hose as a flexible line element is to be preferred.

Claims (18)

1. Duct element, particularly for exhaust ducts of internal-combustion engines, comprising a metallic hose (1, 10, 15, 20, 25, 29, 36, 44, 50) which is corrugated and/or is wound from at least one strip, and means (4, 11, 21, 26, 30, 37, 45, 52) arranged externally of and along this metallic hose and connected to the coupling ends of the metallic hose for the flexible support of the metallic hose against changes in length arising in operation,
   characterised in that
   an annular, flexible, resiliently elastic damping cushion (7, 14, 18, 22, 27, 31 to 35, 38, 46, 51) of heat-resistant material is arranged between the metallic hose (1, 10, 15, 20, 25, 29, 36, 44, 50) and the longitudinal support means (4, 11, 21, 26, 30, 37, 45, 52), and that between its ends the longitudinal support is radially widened into a barrel shape.
2. Duct element according to claim 1,
   characterised in that
   the longitudinal support (4, 11, 17, 21, 26, 30, 52) is formed by a hollow cylindrical metallic wire braid.
3. Duct element according to claim 1,
   characterised in that
   the longitudinal support (37) is formed by a tubular part that is radially widened between its ends into a barrel shape, and that between its ends the part has slits (40) that are circumferentially uniformly distributed and are parallel to the axis.
4. Duct element according to claim 1,
   characterised in that
   the longitudinal support (45) is formed by wires, cables or the like uniformly distributed over the periphery of the metallic hose (44) and parallel to the axis of the metallic hose, the ends of the wires, cables or the like being secured or at least indirectly fixed to the ends of the metallic hose.
5. Duct element according to claim 1,
   characterised in that
   a hollow cylindrical supporting jacket (53) is provided radially externally of and bearing against the longitudinal support (52), and that the supporting jacket is axially secured, for example secured at one of its ends (at 54) to the associated end of the metallic hose.
6. Duct element according to claim 5,
   characterised in that
   the supporting jacket (53) is a flexible metallic hose.
7. Duct element according to claim 6,
   characterised in that
   the supporting jacket (53) is an interlocked hose made from a metallic strip by winding.
8. Duct element according to claim 1,
   characterised in that
   the damping cushion (7, 8, 14, 18, 22, 27, 31 to 35, 38, 46, 51) consists of a knitted metallic wire mesh and/or metallic fibre texture and/or metallic wire braid and/or metallic wire cloth.
9. Duct element according to claim 8,
   characterised in that
   filler and/or lubricant materials are additionally contained in the damping cushion (7, 8, 14, 18, 22, 27, 31 to 35, 38, 46, 51).
10. Duct element according to claim 8,
    characterised in that
    the damping cushion (7, 8, 14, 18, 22, 31 to 35, 46, 51) extends substantially along the whole length of the metallic hose (1, 10, 15, 20, 29, 44, 50) between the coupling ends of the latter.
11. Duct element according to claim 8,
    characterised in that
    at least one damping cushion (27, 31 to 35, 38) extends over an axial section of the metallic hose (25, 29, 36).
12. Duct element according to claim 8,
    characterised in that
    the damping cushion (7, 8, 14, 18, 22, 27, 31 to 35, 38, 46, 51) is preformed in accordance with its final mounting location.
13. Duct element according to claim 12,
    characterised in that
    the damping cushion (7, 8, 14, 18, 22, 27, 31 to 35, 38, 46, 51) has a sheath.
14. Duct element according to claim 13,
    characterised in that
    the sheath is a braid jacket, a steel wool jacket, a metallic foil or the like.
15. Duct element according to claim 8,
    characterised in that
    the damping cushion (46) has a multi-layered (47 to 49) construction.
16. Duct element according to claim 15,
    characterised in that
    the layers (47 to 49) of the damping cushion (46) are made of different materials.
17. Duct element according to claim 8,
    characterised in that
    over its axial and/or radial cross-section the damping cushion (7, 8, 14, 18, 22, 27, 31 to 35, 38, 46, 51) has different degrees of compression.
18. Duct element according to claim 8,
    characterised in that
    when the metallic hose (15, 20, 25, 36) is in the form of a corrugated hose the internal circumference of the damping cushion (18, 22, 27, 38) is moulded into at least one turn of the hose corrugation.

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